The invention relates to a non-reinforced film of regenerated cellulose, which is suitable for the production of tubular sausage casings having a seam in the direction of their longitudinal axes. The invention also relates to a process for producing the non-reinforced film of regenerated cellulose and to a sausage casing made of a film according to the invention.
The production of web-shaped cellulose films intended for use as support materials for tubular sausage casings is, for example, described in European Pat. No. 54 162. Film production, tube forming and the finished sausage are shown in the drawings accompanying the patent. However, the films described in that publication are fiber-reinforced and their mechanical properties can therefore not be compared with those of non-reinforced films of cellulose, so-called cellophane films.
Processes have also been described, in which the sausage emulsion is pressed into a tubing which is formed directly at the stuffing horn (U.S. Pat. Nos. 2,607,696, 2,653,432 and 2,686,725). For use in these processes, regenerated cellulose has also been mentioned as a suitable film material.
Furthermore, U.S. Pat. No. 2,698,967 discloses a process for the production of cellulose films, in which a finished cellulose film which has been produced according to the viscose process is humidified to a moisture content of 12 to 15% by weight and then post-stretched 4% to 7% in the transverse direction. This post-stretching in the transverse direction is, however, only intended to compensate for the transverse shrinkage which occurred in the preceding drying process. The reference also states that dried cellulose films usually swell when they are remoistened with water and thereby extend 30% in the transverse direction and shrink 10% in the longitudinal direction. The post-stretched films, on the other hand, are said to exhibit more uniform properties in the transverse and longitudinal directions.
This swelling behavior of the cellulose casings gives rise to serious disadvantages when the casings are used as tubular sausage casings, because upon filling with sausage meat and in the following scalding process the cellulose film absorbs water and expands in the circumferential direction. Consequently, the sausage casing looks flabby and wrinkled and it is difficult to peel it from the sausage.